What machine did Leonardo da Vinci design to test how wings might flap?

Leonardo da Vinci designed an ornithopter to investigate flapping-wing flight.

An ornithopter is an aircraft that generates lift by flapping wings, imitating the motion of birds or bats. Leonardo’s studies included large wings, frames, pedals, and levers intended to transfer human motion into wing movement.

His flying-machine work was based on close observation of birds and on experiments with air resistance, balance, and muscle power. He recognized that a human pilot would have difficulty producing enough power for sustained flapping flight, but he continued to explore the mechanical problem through drawings and models.

An ornithopter is different from the aerial screw in Leonardo’s notebooks. The aerial screw uses a rotating helical surface, while an ornithopter uses reciprocating wing beats. Leonardo did not achieve powered human flight, yet his studies helped establish a habit of analyzing flight through anatomy, mechanics, and aerodynamic forces.